煤基合成丙烯全过程模拟与废水利用

Coal-based olefins process simulation and wastewater reuse

对5000 t/d煤气化经甲醇制备丙烯的工艺进行了废水资源化利用的研究,对该过程进行了全流程模拟,获得准确的工艺数据,如煤气化消耗用水量、甲醇及烯烃合成中排放的废水排放量、组成及pH等性质。提出将废水代替新鲜水作为汽化剂用于煤气化炉的用水策略并进行了模拟,研究了废水用作汽化剂对合成气组成和汽化温度的影响。结果表明,在煤气化条件下,废水中甲醇等有机物污染物基本可以完全转化为CO,H2,CH4及部分CO2和H2O,在合成气中的残留量低于10 ppb,且气化温度仍保持在1 500℃左右。实施改造方案可行后,可实现节水24万t/年。

A new water utilization strategy was proposed in this paper. The main future is that the wastewater is recycled to be as a feedstock for coal gasifier. An integrated coalbased propylene flowsheet considering the new water recycling was constructed at first, consisting of three major sections, i. e. , coal gasification, methanol synthesis and methanol to propylene, based on commercial process with coal gasification capacity of 5 000 t/d. Some essential information of each stream was obtained, such as the freshwater consumption in coal gasification, properties of wastewater produced in methanol and propylene synthesis process. The results show that coal gasification temperature is not strongly changed that is keeping at about 1 500 ~（2, there is not evident influence on crude synthesis gas compgs, ition although some contaminations were became into CO, H2, CH4, CO2 and H20, and the residue of contaminations in the synthesis gas is below 10 ppb. Freshwater saving will be up to 240, 000 tons/year if the plant was constructed.